Drip irrigation emitter and drip irrigation device equipped with same

ABSTRACT

A drip irrigation emitter ( 1 ), which comprises a low pressure stop filter ( 5 ), a pressure reduction channel ( 8 ), and a diaphragm ( 10 ), is disposed on the inner wall surface of a flow pipe ( 3 ) through which the irrigation liquid flows. The low pressure stop filter ( 5 ) has a hydrophobic surface and prevents inflow of the irrigation liquid when the fluid pressure is lower than an established value. The pressure reduction channel ( 8 ) reduces the pressure of the irrigation liquid. The diaphragm ( 10 ) changes the degree of opening of the pressure reduction channel ( 8 ) according to the fluid pressure of the irrigation liquid. The drip irrigation emitter ( 1 ) can be manufactured at low cost as a result of being a one-piece molding. The drip irrigation device comprising the drip irrigation emitter ( 1 ) stably ejects the irrigation liquid even when the liquid pressure is low.

TECHNICAL FIELD

The present invention relates to a drip irrigation emitter and a dripirrigation apparatus including the drip irrigation emitter, andparticularly to a drip irrigation emitter and a drip irrigationapparatus including the drip irrigation emitter which are suitable forgrowing plants.

BACKGROUND ART

Conventionally, drip irrigation systems (also known as trickleirrigation systems or micro irrigation systems) have been employed tosupply water and irrigation liquid such as liquid fertilizer to theplants to be grown into the soil in the agricultural land, theplantation or the like.

In such drip irrigation systems, for example, a filter, a fertigationapparatus (a chemigation apparatus if necessary), a back flow preventionapparatus, a main pipe, and the like are connected in sequence on thedownstream side of a pump that brings up water from the water source,and an elongated drip watering tube is connected to the channelterminal. In addition, the drip watering tube is laid on the soil inwhich plants are grown.

Here, the drip watering tube ejects the irrigation liquid in the tubemain body at a predetermined ejection rate (or ejection speed) per unittime from a plurality of ejection ports provided to the elongated tubemain body at predetermined intervals along the longitudinal direction ofthe tube main body. Thus, the irrigation liquid is slowly supplied tothe soil outside of the drip watering tube (that is, drip irrigation isperformed).

With such a drip watering tube, water and fertilizer can be saved. Inaddition, by supplying water at a moderate supply speed, the oxygenrequired for plant roots can be ensured in the soil. As a result, thegrowing of plants can be favorably managed.

In such a drip watering tube, a drip irrigation emitter for controllingthe ejection amount of the irrigation liquid from each ejection port perunit time is provided at each ejection port.

In this drip irrigation emitter, the irrigation liquid flowing in thetube main body flows in the drip irrigation emitter through the inletand flows through a pressure reduction channel (which is calledlabyrinth) in the drip irrigation emitter in such a manner that thepressure of the irrigation liquid is reduced, and then, the irrigationliquid is ejected from the ejection port connected on the downstreamside of the pressure reduction channel.

Some conventional drip irrigation emitters are provided with a so-calleddifferential pressure control mechanism (pressure correction function).Such conventional drip irrigation emitters have, for example, athree-component structure in which an elastic film (for example,silicone rubber film) such as a diaphragm is sandwiched by an inflowside member and an ejection side member, as with the drip irrigationemitter (emitter unit) disclosed in PTL 1.

The drip irrigation emitter disclosed in PTL 1 controls theopening/closing of the entrance port of the drip irrigation emitter andthe flow rate from the exit port of the drip irrigation emitter, by theoperation of a diaphragm (film) in accordance with the liquid pressureoutside of the drip irrigation emitter and in a tube main body.

To be more specific, in the drip irrigation emitter disclosed in PTL 1,when the liquid pressure outside of the drip irrigation emitter isincreased to a certain level, the diaphragm that is so disposed as toshield the entrance is deflected by the liquid pressure toward theoutlet. As a result, the entrance is opened. When the liquid pressure isfurther increased, the amount of the deflection of the diaphragm towardthe outlet is increased, and consequently the cross-sectional size ofthe channel in the outlet is reduced. As a result, the ejection amountis limited.

As disclosed in paragraph [0004] of PTL 1, in the drip irrigationemitter, the ejection speed of the irrigation liquid from the dripirrigation emitter (emitter) has substantially no relation with thevariation in pressure of the irrigation liquid supplied to the dripirrigation emitter.

Therefore, the drip irrigation emitter has been expected to limitnon-uniformity in the ejection amount of the irrigation liquid betweenthe drip irrigation emitters disposed on the upstream side (highpressure side) and the downstream side (low pressure side) in the tubemain body, to thereby uniformize the growing of plants in the entiresoil.

CITATION LIST Patent Literature

PTL 1

Japanese Patent Application Laid-Open No. 2010-46094

SUMMARY OF INVENTION Technical Problem

However, the drip irrigation emitter disclosed in PTL 1 requires arelatively high liquid pressure to open the entrance by elasticallydeforming the diaphragm. Therefore, when used at a relatively highliquid pressure by using a high pressure pump, the drip irrigationemitter would function with no problem. However, when used at a lowliquid pressure, the diaphragm cannot be elastically deformed in aproper manner, and therefore the drip irrigation emitter may notsufficiently function.

The drip irrigation emitter disclosed in PTL 1 has the following fourproblems.

(First Problem)

The drip irrigation emitter disclosed in PTL 1 requires a large numberof components, and thus incurs increase in the size of the dripirrigation emitter (in particular, increase in the size in the heightdirection). When such a drip irrigation emitter is disposed in the tubemain body, the area occupancy of the drip irrigation emitter in the tubemain body with respect to the cross-section of the channel is naturallylarge.

In this manner, the drip irrigation emitter on the upstream side servesas a large hindrance laid on the channel and blocks the drip irrigationemitter on the downstream side from the irrigation liquid flowing in thetube main body. Thus, the drip irrigation emitter hinders the flow ofthe irrigation liquid, and consequently the pressure drop in the tubemain body is undesirably increased.

Therefore, when a high pressure pump is not used, the drip irrigationemitter disclosed in PTL 1 cannot be used for a long-distance wateringutilizing a considerably long drip watering tube. If the drip irrigationemitter disclosed in PTL 1 is used for the long-distance watering, theejection amount of the irrigation liquid may be non-uniform.

(Second Problem)

In addition, the drip irrigation emitter disclosed in PTL 1 may have aproblem of assembly error of the above-described three components. Inthis case, the operations of diaphragms (films) are non-uniform, and asa result, the ejection amount of the irrigation liquid is non-uniform.

(Third Problem)

Further, in the drip irrigation emitter disclosed in PTL 1, the materialcost may be raised when silicone rubber is used for the diaphragm.

(Fourth Problem)

Furthermore, the drip irrigation emitter disclosed in PTL 1 requires thestep of assembling the three components after the three components areseparately manufactured, thus raising the manufacturing cost.

Given the above-mentioned problems, a first object of the presentinvention is to provide a drip irrigation emitter and a drip irrigationapparatus including the drip irrigation emitter which can properlyperform drip irrigation even when the liquid pressure of irrigationliquid in the flow pipe is low.

A second object of the present invention is to provide a drip irrigationemitter and a drip irrigation apparatus including the drip irrigationemitter which can properly perform a long-distance irrigation even whenthe liquid pressure of irrigation liquid is low, can stabilize theejection amount of the irrigation liquid, and can achieve cost reductionby reducing the manufacturing cost, number of components andmanufacturing steps.

Solution to Problem

To achieve the first objet, the present invention provides the followingdrip irrigation emitter.

-   [1] A drip irrigation emitter for controlling an amount of    irrigation liquid ejected through an ejection port of a flow pipe    through which the irrigation liquid flows, the ejection port    extending through a pipe wall of the flow pipe, the drip irrigation    emitter comprising: a flow channel that allows the irrigation liquid    to flow from an inside of the flow pipe to the ejection port when    the drip irrigation emitter is disposed at a position corresponding    to the ejection port in an inner peripheral surface of the flow    pipe; when the drip irrigation emitter is disposed at a position    corresponding to the ejection port in an inner peripheral surface of    the flow pipe; an inflow part for introducing the irrigation liquid    in the flow pipe into the flow channel; a pressure reduction channel    part disposed on a downstream side relative to the inflow part in    the channel, the pressure reduction channel part being configured to    define a pressure reduction channel, the pressure reduction channel    being configured to allow the irrigation liquid entered from the    inflow part to flow therethrough toward the ejection port while    reducing a pressure of the irrigation liquid; a first plane to be    connected to the inner peripheral surface of the flow pipe; and a    second plane to be located on a central axis side of the flow pipe    relative to the first plane, wherein the inflow part is disposed at    the second plane, has hydrophobicity, and prevents the irrigation    liquid having a liquid pressure lower than a predetermined liquid    pressure from being introduced into the flow channel.-   [2] The drip irrigation emitter according to [1], wherein the inflow    part includes a substrate part, and a plurality of inlets that    extend through the substrate part, the substrate part includes a    front surface included in the second plane, and a rear surface    facing the channel, wherein at least the front surface has    hydrophobicity.-   [3] The drip irrigation emitter according to [2], wherein an inner    peripheral surface of each of the inlets has hydrophobicity.-   [4] The drip irrigation emitter according to [2] or [3], wherein the    inflow part is composed of a hydrophobic material.-   [5] The drip irrigation emitter according to [2] or [3], wherein    hydrophobic coating is applied to the inflow part.-   [6] The drip irrigation emitter according to [4] or [5], wherein the    inflow part includes an irregularity provided on the surface having    hydrophobicity.-   [7] The drip irrigation emitter according to any one of [1] to [6]    further including a diaphragm part disposed on a downstream side    relative to the inflow part in the channel, the diaphragm part being    configured to control a cross-sectional size of the flow channel    through deformation of the diaphragm part in accordance with the    liquid pressure of the irrigation liquid in the flow pipe.-   [8] The drip irrigation emitter according to [7] further including    an opening part that opens to the second plane, and connects the    flow channel and an outside together, wherein the pressure reduction    channel part includes a groove recessed from the first plane, the    groove being configured to define the pressure reduction channel    together with the inner peripheral surface of the flow pipe, the    diaphragm part is disposed at the opening part such that the    diaphragm part is partially exposed to the outside and that the    diaphragm part is deformed toward the inner peripheral surface of    the flow pipe that defines the pressure reduction channel, and the    inflow part, the pressure reduction channel part and the diaphragm    part are integrally formed with a resin material.

To achieve the second object, the present invention provides thefollowing drip irrigation emitter.

-   [9] A drip irrigation emitter for controlling an amount of    irrigation liquid ejected through an ejection port of a flow pipe    through which the irrigation liquid flows, the ejection port    extending through a pipe wall of the flow pipe, the drip irrigation    emitter comprising: a flow channel that allows the irrigation liquid    in the flow pipe to flow from an inside of the flow pipe to the    ejection port when the drip irrigation emitter is disposed at a    position corresponding to the ejection port in an inner peripheral    surface of the flow pipe; an inflow part for introducing the    irrigation liquid in the flow pipe into the flow channel; a pressure    reduction channel part disposed on a downstream side relative to the    inflow part in the channel, the pressure reduction channel part    being configured to define a pressure reduction channel together    with the inner peripheral surface of the flow pipe, the pressure    reduction channel being configured to allow the irrigation liquid    entered from the inflow part to flow therethrough toward the    ejection port while reducing a pressure of the irrigation liquid; a    diaphragm part disposed on a downstream side relative to the inflow    part in the flow channel such that the diaphragm part is partially    exposed in the flow pipe, that the diaphragm is exposed to the    liquid pressure of the irrigation liquid in the flow pipe, and that    the diaphragm is deformed toward the inner peripheral surface of the    flow pipe, a first plane to be connected to the inner peripheral    surface of the flow pipe; and a second plane to be located on a    central axis side of the flow pipe relative to the first plane,    wherein the inflow part is disposed at the second plane, the    diaphragm part limits a height of the flow channel such that the    height of the flow channel decreases as the liquid pressure    increases by being deformed toward the inner peripheral surface of    the flow pipe in accordance with the liquid pressure, and the inflow    part, the pressure reduction channel part and the diaphragm part are    integrally formed with a resin material.-   [10] The drip irrigation emitter according to [9], wherein the    diaphragm part is disposed between the ejection port and the    pressure reduction channel part in the flow channel.-   [11] The drip irrigation emitter according to claim 9 or 10, wherein    the diaphragm part includes a thin central wall part having a curved    shape protruding in a direction away from the inner peripheral    surface of the flow pipe defining the pressure reduction channel,    and a thin peripheral wall part connected to an outer peripheral    edge of the central wall part in such a manner as to surround the    central wall part, the peripheral wall part having a shape gradually    expanding in the direction away from the inner peripheral surface of    the flow pipe.-   [12] The drip irrigation emitter according to [11] further including    an opening part that opens to the second plane and connects the flow    channel and an outside together, wherein the diaphragm part is so    disposed at the opening part as to be partially exposed to the    outside.

To achieve the first object or the second object, the present inventionprovides the following drip irrigation apparatus.

-   [13] A drip irrigation apparatus including: a flow pipe through    which irrigation liquid flows, the flow pipe including an ejection    port that extends through a pipe wall; and the drip irrigation    emitter according to any one of [1] to [12] disposed on an inner    peripheral surface of the flow pipe at a position corresponding to    the ejection port, the drip irrigation emitter being configured to    control an amount of the irrigation liquid ejected from the ejection    port.

Advantageous Effects of Invention

According to the present invention, even when the liquid pressure ofirrigation liquid in a flow pipe is low, drip irrigation can be properlyperformed.

With the invention according to [1], the lower limit of the liquidpressure of irrigation liquid that flows in the flow channel of the dripirrigation emitter main body can be controlled, by the hydrophobicity ofthe inflow part, to a level lower than that of a conventional art. Thus,even when the liquid pressure of the irrigation liquid in the flow pipe(in other words, outside of the flow channel of the drip irrigationemitter main body) is low, the irrigation liquid can be properly usedfor drip irrigation.

With the invention according to [2], a portion of the inflow partexposed to the irrigation liquid outside of the flow channel of the dripirrigation emitter main body has hydrophobicity. Thus, the inflow of theirrigation liquid into the flow channel of the drip irrigation emittermain body can be properly limited.

With the invention according to [3], capillarity at the inlet can besurely prevented and thus the inflow of the irrigation liquid can beproperly limited.

With the invention according to [4], the hydrophobicity of the inflowpart can be achieved with a small number of components.

With the invention according to [5], the hydrophobicity of the inflowpart does not depend on the material of the inflow part, and thus thedegree of freedom of selection of the material of the inflow part can beimproved.

With the invention according to [6], the lower limit of the liquidpressure of the irrigation liquid that flows into the flow channel ofthe drip irrigation emitter main body can be adjusted to a slightly highlevel. Thus, the degree of freedom of selection of the liquid pressurein the case where the drip irrigation emitter is used under a lowpressure can be improved.

With the invention according to [7], even when the drip irrigationemitter is used under a high pressure, the flow rate of the irrigationliquid toward the ejection port in the flow channel of the dripirrigation emitter can be limited by the diaphragm part. Thus, even whenthe drip irrigation emitter is used under a high pressure, the ejectionamount of the irrigation liquid can be properly controlled.

With the invention according to [8], a small-sized and inexpensive dripirrigation emitter which is excellent in control of the ejection ratecan be accurately manufactured with fewer steps by integral moldingusing a resin material. Thus, even when the liquid pressure of theirrigation liquid supplied into the flow pipe from the water source sideis low, long-distance watering can be properly performed. In addition,the ejection amount of the irrigation liquid can be stabilized. Further,cost reduction can be achieved by reducing the manufacturing cost,number of components and manufacturing steps.

In addition, with the present invention, even when the liquid pressureof the irrigation liquid is low, long-distance watering can be properlyperformed, and in addition, the ejection amount of the irrigation liquidcan be stabilized. Further, cost reduction can be achieved by reducingthe manufacturing cost, number of components and manufacturing steps.

With the invention according to [9], the drip irrigation emitter canhave a plate shape. Thus, pressure reduction by the pressure reductionchannel and limitation on the height of the flow channel by thediaphragm part can be performed, and a small-sized and inexpensive dripirrigation emitter which is excellent in control of the ejection ratecan be accurately manufactured with fewer steps by integral moldingusing a resin material. Therefore, even when the liquid pressure (inother words, flow pressure) of the irrigation liquid is low,long-distance watering can be properly performed. In addition, theejection amount of the irrigation liquid can be stabilized. Further,cost reduction can be achieved by reducing the manufacturing cost,number of components and manufacturing steps.

With the invention according to [10], the diaphragm part disposed on thedownstream side of the pressure reduction channel part can suitably andefficiency limit the height of the flow channel by utilizing thedifference in pressure between the irrigation liquid in the flow channelwhose pressure has been reduced by the pressure reduction channel, andthe irrigation liquid outside of the flow channel to which the diaphragmpart is exposed. In addition, the diaphragm part can be disposed at aposition laterally shifted from a position immediately above ejectionport. Thus, even when plant roots, small rocks, sand, insects and thelike have intruded from the ejection port, it is possible to prevent theplant roots, small rocks, sand, insects and the like from having aninfluence on the operation of diaphragm part.

With the invention according to [11], the diaphragm part can be formedin a shape suitable for efficiently receiving the liquid pressure of theirrigation liquid outside of the flow channel and deforming toward theinner peripheral surface of the flow pipe. Thus, the height of the flowchannel can be further properly limited.

With the invention according to [12], the diaphragm part can be readilydisposed at a position near the inner peripheral surface of the flowpipe in such a manner that the liquid pressure of the irrigation liquidoutside of the flow channel can be properly received. Thus, thedeformation amount of the diaphragm part required for limitation on theheight of the flow channel can be limited, and as a result, thedurability of the thin diaphragm part can be ensured, thus achieving alonger lifetime of the drip irrigation emitter.

With the invention according to [13], even when the liquid pressure ofthe irrigation liquid in the flow pipe is low, drip irrigation can beproperly performed. Alternatively, with the invention according to [13],even when the liquid pressure of the irrigation liquid is low,long-distance watering can be properly performed, and in addition, theejection amount of the irrigation liquid can be stabilized. Further,reduction in manufacturing cost can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a drip irrigation emitter according toEmbodiment of the present invention as viewed from the top side;

FIG. 2 is a perspective view of the drip irrigation emitter illustratedin FIG. 1 as viewed from the bottom side;

FIG. 3 is a plan view of the drip irrigation emitter illustrated in FIG.1;

FIG. 4 is a sectional view of the drip irrigation emitter illustrated inFIG. 1 taken along line A-A of FIG. 3;

FIG. 5 is a bottom view of the drip irrigation emitter illustrated inFIG. 1;

FIG. 6 is a sectional view schematically illustrating a drip irrigationapparatus according to Embodiment of the present invention;

FIG. 7 is an enlarged cross sectional view of a low-pressure stop filterpart (corresponding to frame B of FIG. 4);

FIG. 8 is an enlarged cross sectional view illustrating a firstmodification of the low-pressure stop filter part;

FIG. 9 is an enlarged cross sectional view illustrating a secondmodification of the low-pressure stop filter part;

FIGS. 10A to 10C are schematic views illustrating an exemplary operationof the low-pressure stop filter part;

FIG. 11 is an enlarged cross sectional view of a diaphragm part(corresponding to frame D of FIG. 4); and

FIGS. 12A to 12C are schematic views illustrating an exemplary operationof the diaphragm part.

DESCRIPTION OF EMBODIMENTS

In the following, a drip irrigation emitter according to Embodiment ofthe present invention and a drip irrigation apparatus including the dripirrigation emitter will be described with reference to FIGS. 1 to 12.

FIG. 1 is a perspective view of drip irrigation emitter 1 in Embodimentas viewed from the top side of drip irrigation emitter 1. FIG. 2 is aperspective view of drip irrigation emitter 1 as viewed from the bottomside of drip irrigation emitter 1. FIG. 3 is a plan view of dripirrigation emitter 1. FIG. 4 is a sectional view of drip irrigationemitter 1 taken along line A-A of FIG. 3. FIG. 5 is a bottom view ofdrip irrigation emitter 1. FIG. 6 is a sectional view schematicallyillustrating drip watering tube 2 as the drip irrigation apparatus inEmbodiment.

As illustrated in FIG. 6, drip watering tube 2 includes substantiallycylindrical and elongated tube main body 3 serving as a flow pipethrough which the irrigation liquid flows, and drip irrigation emitter 1disposed in tube main body 3.

In addition, as illustrated in FIG. 6, drip irrigation emitter 1 isdisposed on inner peripheral surface 3 a of tube main body 3 at aposition corresponding to ejection port 4 for irrigation liquid, in sucha manner as to cover ejection port 4. Ejection port 4 penetrates innerperipheral surface 3 a and outer peripheral surface 3 b of tube mainbody 3 (in other words, extends through the pipe wall). Drip irrigationemitter 1 is configured to control the ejection rate per unit time ofthe irrigation liquid from the position corresponding to ejection port4.

It is to be noted that, while FIG. 6 illustrates one drip irrigationemitter 1 and one ejection port 4 for convenience, a plurality of dripirrigation emitters 1 and a plurality of ejection ports 4 are disposedalong the longitudinal direction of tube main body 3 at predeterminedintervals.

In addition, in FIG. 6, the left and right sides to the sheet of FIG. 6of the channel in tube main body 3 correspond to the upstream (watersource) side and the downstream side, respectively.

Further, in Embodiment, drip irrigation emitter 1 is integrally formedby resin molding using a metal mold. Examples of the resin material usedfor the resin molding include inexpensive materials such aspolypropylene. In addition, examples of the molding method includeinjection molding.

Furthermore, as illustrated in FIG. 1 to FIG. 6, drip irrigation emitter(drip irrigation emitter main body) 1 has a substantially cuboid plateshape in appearance.

That is, as illustrated in FIG. 1 to FIG. 6, drip irrigation emitter 1has an external shape roughly surrounded by bottom end surface 1 a asthe first plane, top surface 1 b as the second plane, left side surface1 c, right side surface 1 d, front side surface 1 e, and rear sidesurface 1 f. Regarding the vertical and lateral positional relationshipamong the surfaces, see the cross arrow of FIG. 3. As illustrated inFIG. 1 to FIG. 6, top surface 1 b and bottom end surface 1 a, left sidesurface 1 c and right side surface 1 d, and front side surface 1 e andrear side surface 1 f are respectively in parallel to each other. Inaddition, top surface 1 b and bottom end surface 1 a are perpendicularto left side surface 1 c, right side surface 1 d, front side surface 1e, and rear side surface 1 f. Further, top surface 1 b and bottom endsurface 1 a are elongated in the left-right direction.

Drip irrigation emitter 1 is jointed to inner peripheral surface 3 a oftube main body 3 through bottom end surface 1 a. Top surface 1 b islocated on the side opposite to bottom end surface 1 a, in other words,on the side closer to the central axis of tube main body 3 relative tobottom end surface 1 a. In the case where tube main body 3 is formed byextrusion molding using a resin material (such as polyethylene) having afusing point lower than that of drip irrigation emitter 1, the jointingof drip irrigation emitter 1 may be completed simultaneously with thecuring of tube main body 3, with ready-made drip irrigation emitter 1disposed on inner peripheral surface 3 a of tube main body 3 to becured.

<Details of Configuration of Inflow Part>

As illustrated in FIG. 3 and FIG. 4, drip irrigation emitter 1 includeslow-pressure stop filter part 5 provided at a position in the vicinityof a left end portion on top surface 1 b. Low-pressure stop filter part5 serves as an inflow part that allows the irrigation liquid in tubemain body 3 to flow into a flow channel of drip irrigation emitter 1.

As illustrated in FIG. 7, low-pressure stop filter part 5 includeshorizontal filter substrate part 51 and a plurality of inlets 52. Eachinlet 52 is a circular pore that perpendicularly penetrates surface 51 aand rear surface 51 b, that is, extends through filter substrate part51. Filter substrate part 51 includes surface 51 a flush with topsurface 1 b, and rear surface 51 b located on the side opposite tosurface 51 a. Surface 51 a is included in top surface 1 b, and rearsurface 51 b faces hollow part 7 described later. The inner space ofeach inlet 52 defines a starting end of the flow channel of dripirrigation emitter 1.

Here, as illustrated in FIG. 3 to FIG. 7, inlets 52 are aligned in afront-rear direction (vertical direction in FIG. 3 and FIG. 5) at evenintervals, and are also aligned in a left-right direction at evenintervals. Thus, inlets 52 are disposed in a matrix.

In addition, as illustrated in FIG. 3, FIG. 4 and FIG. 7, a plurality ofplate-shaped protrusions 6 each of which are perpendicularly protrudedtoward the upside and elongated in a front-rear direction are aligned ontop surface 1 b including surface 51 a of filter substrate part 51 inthe longitudinal direction (left and right) of top surface 1 b at evenintervals. Protrusions 6 functions as a filter that prevents relativelylarge foreign matters from flowing into the flow channel of dripirrigation emitter 1.

<Low-pressure Stop Filter>

Low-pressure stop filter part 5 has a function (low-pressure stop filterfunction) of preventing irrigation liquid having a pressure lower than apredetermined pressure (which is also referred to as “liquid pressure,”and is, for example, 0.005 MPa) from flowing into the flow channel ofdrip irrigation emitter 1.

Examples of the manner embodying the low-pressure stop filter functionare as follows.

For example, in the case where drip irrigation emitter 1 is made of theabove-described polypropylene, polypropylene itself is ahighly-hydrophobic material (that is, hydrophobic material) having lowsurface energy. For this reason, the low-pressure stop filter functionmay be easily provided to the entirety of low-pressure stop filter part5.

As another example, as illustrated in FIG. 8, hydrophobic coating C suchas fluorine coating using a fluorine coating agent or the like isapplied to surface 51 a of filter substrate part 51 and, if necessary,inner peripheral surface 52 a of inlet 52, to thereby reduce the surfaceenergy. In this manner, a low-pressure stop filter function can belocally provided to low-pressure stop filter part 5.

In addition, in the case of using the hydrophobic material or the caseof using the hydrophobic coating, it is possible to form irregularity onthe surface having hydrophobicity to increase the hydrophobicity asnecessary. The “surface having hydrophobicity” is, for example, asurface composed of a hydrophobic material, or a surface on whichhydrophobic coating is applied. The irregularity may be burrs 52 bprovided at the upper portion of the opening edge of inlet 52 asillustrated in FIG. 9, or irregularity which is formed so as to reflectirregularity provided in a metal mold.

Further, in addition to the above-described examples, the low-pressurestop filter function may be optimized by adjusting the internaldiameter, pitch, number, shape of the opening, thickness, or the like ofinlet 52.

When the liquid pressure of the irrigation liquid in tube main body 3 isincreased to a predetermined pressure (fracture hydraulic pressure),low-pressure stop filter part 5 allows the irrigation liquid to flowinto the flow channel of drip irrigation emitter 1 through inlet 52.Here, from the viewpoint of favorably operating drip irrigation emitter1 under a low pressure, it is desirable to select a sufficiently lowpressure of about 0.005 MPa as exemplified above, for the predeterminedpressure. It should be noted that the predetermined pressure may differdepending on the degree of the hydrophobicity of low-pressure stopfilter part 5. Therefore, when providing low-pressure stop filter part 5with hydrophobicity, it is possible to select, on the basis ofexperiments, elements relating to the required hydrophobicity (thematerial of the above-described low-pressure stop filter part 5, thekind and thickness of the hydrophobic coating, form of the surfacehaving the hydrophobicity, and the like) in consideration of therelationship with a predetermined pressure to be set.

FIGS. 10A to 10C illustrate a specific example of the operation oflow-pressure stop filter part 5.

First, when the liquid pressure outside of the flow channel of dripirrigation emitter 1 is 0 MPa, that is, when the irrigation liquid doesnot exist in drip watering tube 2, low-pressure stop filter part 5 doesnot limit the inflow of the irrigation liquid as a matter of course, asillustrated in FIG. 10.

Next, when the liquid pressure outside of the flow channel of dripirrigation emitter 1 is lower than 0.005 MPa (the above-describedfracture hydraulic pressure), a low-pressure stop filter function basedthe hydrophobicity of low-pressure stop filter part 5 works asillustrated in FIG. 10B. As a result, irrigation liquid 100 in tube mainbody 3 is blocked at surface 51 a of filter substrate part 51 and at theopening of the upper end of inlet 52. Thus, the inflow of irrigationliquid 100 into the flow channel of drip irrigation emitter 1 isprevented (restricted).

Next, when the liquid pressure outside of the flow channel of dripirrigation emitter 1 is equal to or greater than 0.005 MPa, the liquidpressure outside of the flow channel surpasses the hydrophobicity oflow-pressure stop filter part 5 as illustrated in FIG. 10C. Thus,irrigation liquid 100 outside of the flow channel of drip irrigationemitter 1 flows into the flow channel of drip irrigation emitter 1 frominlet 52.

Alternatively, the fracture hydraulic pressure may be 0.01 MPa. From theviewpoint of favorably operating drip irrigation emitter 1 forlong-distance watering under a low pressure, it is desirable that thepredetermined pressure be not unnecessarily increased, and theabove-exemplified fracture hydraulic pressure of 0.01 MPa or the likesuffices.

<Hollow Part>

As illustrated in FIG. 4, FIG. 6 and FIG. 7, rear surface 51 b of filtersubstrate part 51 is disposed above bottom end surface 1 a. Thus, abovebottom end surface 1 a (between bottom end surface 1 a and top surface 1b), hollow part 7 is defined by the difference of elevation betweenbottom end surface 1 a and rear surface 51 b of filter substrate part51.

Hollow part 7 is connected with each inlet 52 at the downstream end ofeach inlet 52. The space surrounded by hollow part 7 and innerperipheral surface 3 a of tube main body 3 that seals the opening at thelower end of hollow part 7 serves as a part of the flow channel of dripirrigation emitter 1. That is, immediately after entering from inlet 52,the irrigation liquid flows in the space (the flow channel) betweenhollow part 7 and inner peripheral surface 3 a of tube main body 3

<Details of Configuration of Pressure Reduction Channel Part>

In addition, as illustrated in FIG. 6, on the downstream side of theflow channel of drip irrigation emitter 1 relative to low-pressure stopfilter part 5, pressure reduction channel part 9 for defining pressurereduction channel 8 that is a part of the flow channel of dripirrigation emitter 1 is disposed.

As illustrated in FIG. 2, FIG. 5 and FIG. 6, pressure reduction channelpart 9 is a long groove that is defined in bottom end surface 1 a fromlow-pressure stop filter part 5 side (left side) toward ejection port 4side (right side) in a meandering shape (or in other words, stream lineshape) meandering in a left-right direction. The long groove is a recess(recessed line) recessed from bottom end surface 1 a.

Pressure reduction channel 8 is defined as a space surrounded bypressure reduction channel part 9 and inner peripheral surface 3 a oftube main body 3 that shields meander-shaped opening 9 a of pressurereduction channel part 9 (long groove).

As illustrated in FIG. 5 and FIG. 6, the upstream end of pressurereduction channel part 9 is connected with the center portion of rightinner surface 7 a of hollow part 7. Thus, pressure reduction channel 8is connected to hollow part 7, at a part on the downstream side ofhollow part 7.

The irrigation liquid having entered from low-pressure stop filter part5 flows into pressure reduction channel 8 from the upstream end ofpressure reduction channel 8, after passing through hollow part 7 (apart of the flow channel).

In pressure reduction channel 8, the irrigation liquid having enteredpressure reduction channel 8 flows toward ejection port 4 side(downstream end side). Since pressure reduction channel 8 has ameandering shape, the pressure drop of the irrigation liquid flowingthrough pressure reduction channel 8 is high. Thus, the flow of theirrigation liquid can be achieved while efficiently reducing thepressure of the irrigation liquid.

<Details of Configuration of Diaphragm Part>

As illustrated in FIG. 4 to FIG. 6, diaphragm part 10 is disposed at thedownstream end of pressure reduction channel part 9.

Diaphragm part 10 is so disposed as to face inner peripheral surface 3 aof tube main body 3 from the upper side in FIG. 4 and FIG. 6 (centralaxis side of tube main body 3), that is, diaphragm part 10 is sodisposed as to be deformed toward inner periphery 3 a. In addition,diaphragm part 10 is partially exposed to the outside of the flowchannel of drip irrigation emitter 1 from the side opposite to innerperiphery 3 a (central axis side of tube main body 3), in such a manneras to be exposed to the liquid pressure of the irrigation liquid outsideof the flow channel of drip irrigation emitter 1. The phrase “partiallyexposed” means that a part of diaphragm part 10 is in communication withthe outside of drip irrigation emitter 1.

In addition, as illustrated in FIG. 6, diaphragm part 10 is disposed ata position shifted toward the upstream side (left side) of the flowchannel from a position which faces ejection port 4 from the upper side(a position immediately above ejection port 4). For example, diaphragmpart 10 is disposed between ejection port 4 and pressure reductionchannel part 9 in the flow channel.

Further, as illustrated in FIG. 4 to FIG. 6 and FIG. 11, diaphragm part10 includes thin-dome shaped central wall part 10 a and thin-peripheralwall part 10 b provided around central wall part 10 a. Central wall part10 a has a circular shape in plan view and bottom view. In addition, asillustrated in FIG. 4 and FIG. 6, central wall part 10 a has, inlongitudinal sectional view, an arch shape (curved shape) that protrudestoward the side opposite to inner peripheral surface 3 a of tube mainbody 3 (toward the upper side in FIG. 4 and FIG. 6, or in a directionaway from inner periphery 3 a). To be more specific, the outer peripheryend portion of central wall part 10 a is provided on a plane in parallelwith top surface 1 b and bottom end surface 1 a, and the center ofcentral wall part 10 a largely protrudes away from inner peripheralsurface 3 a of tube main body 3 in comparison with the other portions.Peripheral wall part 10 b has an annular shape in plan view and bottomview. As illustrated in FIG. 4 to FIG. 6, peripheral wall part 10 b isconnected with the outer peripheral end of central wall part 10 a so asto surround central wall part 10 a. In addition, peripheral wall part 10b has a tapered cylinder shape that is flaring from central wall part 10a toward the outside in a direction away from inner peripheral surface 3a of tube main body 3. In other words, peripheral wall part 10 b has ashape that surrounds central wall part 10 a, and gradually expands in adirection away from inner periphery 3 a. It is to be noted that each ofcentral wall part 10 a and peripheral wall part 10 b may have athickness of 0.1 mm.

Furthermore, as illustrated in FIG. 3, FIG. 4 and FIG. 6, at a positionin top surface 1 b and immediately above diaphragm part 10, opening part12 having a cylindrical inner peripheral surface is provided as a recessin a region from top surface 1 b to the top surface of diaphragm part10. In a sense, opening part 12 opens to top surface 1 b, connects theoutside and the flow channel together, and diaphragm part 10 is fixed insuch a manner that the edge of peripheral wall part 10 b makes closecontact with the peripheral wall of opening part 12. In this sense, theabove-mentioned connection is shielded by diaphragm part 10.

With opening part 12, diaphragm part 10 is partially (only at the topsurface of diaphragm part 10) exposed to the outside of the flow channelof drip irrigation emitter 1.

In addition, diaphragm part 10 is disposed at a recessed position nearerto inner peripheral surface 3 a of tube main body 3 (lower side)relative to top surface 1 b by the thickness (in other words, depth) ofopening part 12.

In accordance with the liquid pressure of the irrigation liquid havingentered opening part 12 outside of the flow channel of drip irrigationemitter 1, diaphragm part 10 deforms toward inner peripheral surface 3 aof tube main body 3. Thus, the height (in other words, cross-sectionalsize) of the flow channel of drip irrigation emitter 1 at the positionwhere diaphragm part 10 is disposed is limited such that the height(cross-sectional size) decreases as the liquid pressure increases.

<Other Configurations>

Furthermore, as illustrated in FIG. 6, on the downstream side ofdiaphragm part 10, outlet 14 as a space upwardly recessed from bottomend surface 1 a is disposed, and ejection port 4 is disposed immediatelybelow outlet 14.

Outlet 14 functions as a channel that leads, to ejection port 4, theirrigation liquid whose flow rate is limited by the limitation on theheight (cross-sectional area) of the flow channel by diaphragm part 10.The irrigation liquid is ejected out of drip watering tube 2 fromejection port 4.

In addition, as illustrated in FIG. 5, at a position in the vicinity ofdiaphragm part 10 on the recessed bottom surface of outlet 14, aplurality of blocking protrusions 17 are disposed. Blocking protrusions17 are configured to prevent plant roots, small rocks, sand, insects andthe like (hereinafter referred to as foreign matters) having intrudedfrom ejection port 4 from being further intruding into pressurereduction channel 8.

Further, as illustrated in FIG. 5, on the front and rear sides ofpressure reduction channel part 9 (on the both sides in a direction inwhich pressure reduction channel 8 extends), blocking grooves 15 aredisposed. Blocking grooves 15 guide foreign matters having intruded fromoutlet 14 to the front and rear of pressure reduction channel 8, tothereby prevent the foreign matters from further intruding into pressurereduction channel 8.

<Operation and Effect of Embodiment>

In Embodiment, only the irrigation liquid in tube main body 3 whoseliquid pressure is equal to or greater than the predetermined liquidpressure passes through inlet 52 of low-pressure stop filter part 5 andflows into the flow channel of drip irrigation emitter 1. Then, afterthe irrigation liquid passes through hollow part 7, the pressure of theirrigation liquid is reduced due to the pressure drop by the form ofpressure reduction channel 8.

Then, after the pressure is reduced at pressure reduction channel 8, theirrigation liquid passes through diaphragm part 10. At this time,diaphragm part 10 is deformed toward inner peripheral surface 3 a oftube main body 3 by the liquid pressure of the irrigation liquid havingentered opening part 12 outside of the flow channel of drip irrigationemitter 1. Thus, the height of the flow channel is reduced by thedeformed amount. The height of the flow channel is limited in thismanner.

Therefore, the flow rate of the irrigation liquid that passes throughdiaphragm part 10 and advances toward ejection port 4 is limited by theinfluence of the limitation on the height of the flow channel bydiaphragm part 10.

Here, two drip irrigation emitters 1 relatively disposed on the upstreamside and downstream side are described.

First, in drip irrigation emitter 1 on the relatively upstream side, theliquid pressure of the irrigation liquid outside of the flow channel isrelatively high. Thus, the amount of the irrigation liquid that flowsinto the flow channel of drip irrigation emitter 1 is relatively large.At the same time, the amount of deformation of diaphragm part 10 isrelatively large, and the amount of the flow limited by diaphragm part10 is also relatively large. This prevents the ejection amount of theirrigation liquid from ejection port 4 from being excessively increased.

On the other hand, in drip irrigation emitter 1 on the relativelydownstream side, the liquid pressure of the irrigation liquid outside ofthe flow channel is relatively low. Thus, the amount of the irrigationliquid that flows into the flow channel of drip irrigation emitter 1 isrelatively low. At the same time, the amount of deformation of diaphragmpart 10 is relatively low, and the amount of the flow limited bydiaphragm part 10 is relatively small. Thus, the ejection amount of theirrigation liquid from ejection port 4 is not excessively reduced.

In this manner, the ejection amount of the irrigation liquid from eachof ejection ports 4 is favorably controlled such that non-uniformity inthe ejection amount of the irrigation liquid from ejection ports 4between the upstream side and downstream side is reduced (to 5 to 10%).

Next, the operation of diaphragm part 10 in Embodiment is described.FIG. 12 illustrates a specific example of the operation of diaphragmpart 10. In this example, the fracture hydraulic pressure of diaphragmpart 10 is 0.01 MPa.

In the specific example of FIGS. 12A to 12C, first, when the liquidpressure is 0 MPa, that is, when no irrigation liquid exists in dripwatering tube 2, the limitation on the height of the flow channel bydiaphragm part 10 is not performed as a matter of course as illustratedin FIG. 12A. The height of the flow channel in this case is 0.25 mm, forexample. It is to be noted that, as illustrated in FIG. 12A, the heightof the flow channel is defined as the shortest distance between thepoint where central wall part 10 a and peripheral wall part 10 b areconnected, which is the lower end portion of diaphragm part 10, andinner peripheral surface 3 a of tube main body 3.

Next, when the liquid pressure is equal to or greater than 0.01 MPa (theabove-described fracture hydraulic pressure) and smaller than 0.05 MPa,diaphragm part 10 is downwardly deformed by the liquid pressure ofirrigation liquid 100 outside of the flow channel as illustrated in FIG.12B. Thus, the point where central wall part 10 a and peripheral wallpart 10 b are connected is put down, and as a result, the height of theflow channel is limited to 0.15 mm.

Next, when the liquid pressure is equal to or greater than 0.05 MPa andequal to or smaller than 0.1 MPa, diaphragm part 10 is downwardlydeformed more than the case of FIG. 12B as illustrated in FIG. 12C.Thus, the point where central wall part 10 a and peripheral wall part 10b are connected is further put down, and as a result, the height of theflow channel is limited to 0.1 mm.

According to Embodiment, by the hydrophobicity of low-pressure stopfilter part 5, the lower limit of the liquid pressure of the irrigationliquid that flows into the flow channel of drip irrigation emitter 1 canbe controlled at a pressure lower than that of the conventional case(specifically, in the case where the pressure is mechanically controlledby the elasticity of the diaphragm). Thus, even when the liquid pressureof the irrigation liquid outside of the flow channel of drip irrigationemitter 1 is low, the irrigation liquid can be properly used for dripirrigation.

In addition, when hydrophobicity is provided at at least surface 51 a offilter substrate part 51 of low-pressure stop filter part 5, a portionof low-pressure stop filter part 5 exposed to the irrigation liquid ofthe flow channel of drip irrigation emitter 1 has hydrophobicity. Thus,the inflow of the irrigation liquid into the flow channel of dripirrigation emitter 1 can be properly controlled.

Further, when inner peripheral surface 52 a of inlet 52 hashydrophobicity, the inflow of the irrigation liquid can be furtherproperly controlled by surely suppressing capillarity in inlet 52.

Furthermore, when low-pressure stop filter part 5 is made of ahydrophobic material, the hydrophobicity of low-pressure stop filterpart 5 can be achieved with a small number of components.

In addition, when the hydrophobicity of low-pressure stop filter part 5is achieved by hydrophobic coating, the hydrophobicity of low-pressurestop filter part 5 is obtained regardless of the material oflow-pressure stop filter part 5. Thus, the degree of freedom ofselection of the material of low-pressure stop filter part 5 can beimproved.

Further, when an irregularity is formed on the surface of low-pressurestop filter part 5 having the hydrophobicity, the lower limit of theliquid pressure of the irrigation liquid that flows into the flowchannel of drip irrigation emitter 1 can be adjusted to a slightly highlevel. Thus, when drip irrigation emitter 1 is used under a lowpressure, the degree of freedom of selection of the liquid pressure ofthe entering irrigation liquid can be improved.

Furthermore, by providing diaphragm part 10, even when drip irrigationemitter 1 is used under a high pressure, the ejection amount of theirrigation liquid can be properly controlled.

In addition, small-sized and inexpensive drip irrigation emitter 1 whichis excellent in control of the ejection rate can be accuratelymanufactured in reduced steps by integral molding of a resin material.In this manner, the volume occupancy of drip irrigation emitter 1 intube main body 3 can be reduced. Thus, excessive pressure drop of theirrigation liquid in tube main body 3 can be prevented. As a result,even when the liquid pressure of the irrigation liquid supplied from thewater source side to drip watering tube 2 is low, a liquid pressureenough to allow the liquid to pass through low-pressure stop filter part5 can be ensured also on the downstream side of tube main body 3.Consequently, long-distance watering can be properly performed at astable ejection rate. In addition, since drip irrigation emitter 1 isintegrally molded, malfunction of diaphragm part 10 due to assemblyerror is not caused. Thus, the ejection amount of the irrigation liquidcan be further stabilized. Further, it is not necessary to use expensivematerials such as silicone rubber for diaphragm part 10, and, basically,one inexpensive resin material may be used. Therefore, manufacturingcost can be reduced. In addition, in comparison with the case wherethree components are assembled as disclosed in PTL 1, the number ofcomponents and manufacturing steps can be surely reduced, and thereforereduction in manufacturing cost can be achieved.

Further, diaphragm part 10 disposed on the downstream side of pressurereduction channel part 9 can properly and efficiency limit the height ofthe flow channel by utilizing the difference in pressure between theirrigation liquid in the flow channel whose pressure has been reduced bypressure reduction channel 8, and the irrigation liquid outside of theflow channel to which diaphragm part 10 is exposed. That is, since theliquid pressure of the irrigation liquid in the flow channel whoseliquid pressure has been reduced is sufficiently low, the liquidpressure of the irrigation liquid in the flow channel does not hinderthe deformation operation of diaphragm part 10 by the irrigation liquidoutside of the flow channel having a relatively high pressure.

Furthermore, diaphragm part 10 is disposed at a position shifted from aposition immediately above ejection port 4 along the flow direction ofthe flow channel, and thus, even when foreign matters intrude fromejection port 4, it is possible to prevent the foreign matters fromhaving an influence on the operation of diaphragm part 10.

In addition, when central wall part 10 a receives a liquid pressure fromthe upper side, diaphragm part 10 is deflected so as to cancel theupward curvature and expanded outward in the radial direction, byutilizing the elasticity of the resin material itself. At the same time,peripheral wall part 10 b turns downward with a connecting point(annular connecting section) where peripheral wall part 10 b and openingpart 12 are connected as the turning axis. Thus, the connecting pointbetween peripheral wall part 10 b and central wall part 10 a fordetermining the height of the flow channel can be smoothly displaceddownward. Thus, diaphragm part 10 has a shape suitable for efficientlyreceiving the liquid pressure of the irrigation liquid outside of theflow channel so as to be deformed toward inner peripheral surface 3 a oftube main body 3 (downward). Consequently, the height of the flowchannel can be further properly limited.

Further, diaphragm part 10 can be readily disposed at a position nearinner peripheral surface 3 a of tube main body 3 in terms of designingand manufacturing, in such a manner that the liquid pressure of theirrigation liquid outside of the flow channel can be properly received.Thus, the deformation amount of the diaphragm part 10 required forlimiting the height of the flow channel can be limited. As a result, thedurability of thin diaphragm part 10 can be ensured and a long productlifetime can be achieved.

Furthermore, in the case where a plurality of drip irrigation emitters 1are respectively disposed at a plurality of ejection ports 4, theejection amount of the irrigation liquid from ejection ports 4 can befavorably controlled with the above-described operation of diaphragmpart 10 such that difference in the amount of the ejected irrigationliquid among the ejection ports 4 on the upstream side and downstreamside is small (limited to 5 to 10%). This effect can be surely achievedeven in the case of a long-distance watering using irrigation liquidhaving a low liquid pressure, since the structure of diaphragm part 10of drip irrigation emitter 1 is designed such that the pressure drop intube main body 3 is moderated as described above.

It should be noted that, the present invention is not restricted to theabove-mentioned Embodiment, and may be variously modified as far as thefeatures of the present invention are included. For example, dripirrigation emitter 1 may have a configuration in which: low-pressurestop filter part 5 is provided; and diaphragm part 10 is not provided orother diaphragm part is provided. In this case, drip irrigation emitter1 has at least an effect other than the effect of low-pressure stopfilter part 5 among the above-described effects. In addition, dripirrigation emitter 1 may have a configuration in which: diaphragm part10 is provided; and low-pressure stop filter part 5 is not provided orother inflow part is provided. In this case, drip irrigation emitter 1has at least an effect other than the effect of diaphragm part 10 amongthe above-described effects.

For example, the present invention can be effectively applied even tothe triple-component drip irrigation emitter disclosed in PTL 1.

This application is entitled to and claims the benefit of JapanesePatent Application Nos. 2012-118551 and 2012-118552 filed on May 24,2012, the disclosure each of which including the specification, drawingsand abstract is incorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to easily provide adrip irrigation emitter in which suitable dropping of irrigation liquidis properly performed using the pressure irrigation liquid to bedropped. Therefore, it is expected that the emitter is broadly appliedin the technical fields of drip irrigation, an endurance test and thelike where dropping for a long period of time are desired, and that thefurther development in the technical fields is achieved.

REFERENCE SIGNS LIST

-   1 Drip irrigation emitter-   2 Drip watering tube-   3 Tube main body-   3 a Inner periphery-   4 Ejection port-   5 Low-pressure stop filter part-   8 Pressure reduction channel-   9 Pressure reduction channel part-   9 a Opening-   10 Diaphragm part

The invention claimed is:
 1. A drip irrigation emitter for controllingan amount of irrigation liquid ejected through an ejection port of aflow pipe through which the irrigation liquid flows, the ejection portextending through a pipe wall of the flow pipe, the drip irrigationemitter comprising: a flow channel that allows the irrigation liquid toflow from an inside of the flow pipe to the ejection port when the dripirrigation emitter is disposed at a position corresponding to theejection port in an inner peripheral surface of the flow pipe; a firstplane to be connected to the inner peripheral surface of the flow pipe;a second plane to be located on a central axis side of the flow piperelative to the first plane; an inflow part, disposed at the secondplane, having hydrophobicity, for introducing the irrigation liquid inthe flow pipe into the flow channel while preventing the irrigationliquid having a liquid pressure lower than a predetermined liquidpressure from introducing into the flow channel; a pressure reductionchannel part disposed on a downstream side relative to the inflow partin the channel, the pressure reduction channel part being configured todefine a pressure reduction channel, the pressure reduction channelbeing configured to allow the irrigation liquid entered from the inflowpart to flow therethrough toward the ejection port while reducing apressure of the irrigation liquid; and a diaphragm part that includes: acentral wall part having a curved shape protruding in a direction awayfrom the inner peripheral surface of the flow pipe defining the pressurereduction channel, and a peripheral wall part connected to an outerperipheral edge of the central wall part in such a manner as to surroundthe central wall part, the peripheral wall part having a shape of atapered cylinder gradually expanding in the direction away from theinner peripheral surface of the flow pipe; wherein the inflow partincludes: a substrate part that comprises a front surface included inthe second plane, and a rear surface facing the channel, and a pluralityof inlets that extend through the substrate part, wherein the inflowpart is composed of a hydrophobic material or hydrophobic coating isapplied to the inflow part, wherein the inflow part includes anirregularity provided on a surface having hydrophobicity, and whereineach of the plurality of inlets has a circular opening.
 2. The dripirrigation emitter according to claim 1, wherein an inner peripheralsurface of each of the inlets has hydrophobicity.
 3. The drip irrigationemitter according to claim 1, further comprising a diaphragm partdisposed on a downstream side relative to the inflow part in thechannel, the diaphragm part being configured to control across-sectional size of the flow channel through deformation of thediaphragm part in accordance with the liquid pressure of the irrigationliquid in the flow pipe.
 4. The drip irrigation emitter according toclaim 3, further comprising an opening part that opens to the secondplane, and connects the flow channel and an outside together, whereinthe pressure reduction channel part includes a groove recessed from thefirst plane, the groove being configured to define the pressurereduction channel together with the inner peripheral surface of the flowpipe, wherein the diaphragm part is disposed at the opening part suchthat the diaphragm part is partially exposed to the outside and that thediaphragm part is deformed toward the inner peripheral surface of theflow pipe that defines the pressure reduction channel, and wherein theinflow part, the pressure reduction channel part and the diaphragm partare integrally formed with a resin material.
 5. A drip irrigationapparatus comprising: a flow pipe through which irrigation liquid flows,the flow pipe including an ejection port that extends through a pipewall; and the drip irrigation emitter according to claim 1 disposed onan inner peripheral surface of the flow pipe at a position correspondingto the ejection port, the drip irrigation emitter being configured tocontrol an amount of the irrigation liquid ejected from the ejectionport.
 6. A drip irrigation emitter for controlling an amount ofirrigation liquid ejected through an ejection port of a flow pipethrough which the irrigation liquid flows, the ejection port extendingthrough a pipe wall of the flow pipe, the drip irrigation emittercomprising: a flow channel that allows the irrigation liquid in the flowpipe to flow from an inside of the flow pipe to the ejection port whenthe drip irrigation emitter is disposed at a position corresponding tothe ejection port in an inner peripheral surface of the flow pipe; aninflow part for introducing the irrigation liquid in the flow pipe intothe flow channel; a pressure reduction channel part disposed on adownstream side relative to the inflow part in the flow channel, thepressure reduction channel part being configured to define a pressurereduction channel together with the inner peripheral surface of the flowpipe, the pressure reduction channel being configured to allow theirrigation liquid entered from the inflow part to flow therethroughtoward the ejection port while reducing a pressure of the irrigationliquid; a diaphragm part disposed on a downstream side relative to theinflow part in the flow channel such that the diaphragm part ispartially exposed in the flow pipe, that the diaphragm is exposed to theliquid pressure of the irrigation liquid in the flow pipe, and that thediaphragm is deformed toward the inner peripheral surface of the flowpipe; a first plane to be connected to the inner peripheral surface ofthe flow pipe; a second plane to be located on a central axis side ofthe flow pipe relative to the first plane; and an opening part thatopens to the second plane and the flow channel and connects the flowchannel and an outside together, wherein the inflow part is disposed atthe second plane, wherein the diaphragm part limits a height of the flowchannel such that the height of the flow channel decreases as the liquidpressure increases by being deformed toward the inner peripheral surfaceof the flow pipe in accordance with the liquid pressure, wherein theinflow part, the pressure reduction channel part and the diaphragm partare integrally formed with a resin material, wherein the diaphragm partincludes: a central wall part having a curved shape protruding in adirection away from the inner peripheral surface of the flow pipedefining the pressure reduction channel, and a peripheral wall partconnected to an outer peripheral edge of the central wall part in such amanner as to surround the central wall part, the peripheral wall parthaving a shape of a tapered cylinder gradually expanding in thedirection away from the inner peripheral surface of the flow pipe,wherein a first end of the tapered cylinder is located on the firstplane side and a second end of the tapered cylinder is located on thesecond plane side, the first end having a diameter smaller than adiameter of the second end, wherein the diaphragm part is so disposed inthe opening part as to be partially exposed to the outside, and whereinan outer peripheral edge of the peripheral wall part is fixed to aninner peripheral surface of the opening part such that a surface of theperipheral wall part comes into contact with the inner peripheralsurface of the opening part when the diaphragm part is deformed towardthe inner peripheral surface of the flow pipe.
 7. The drip irrigationemitter according to claim 6, wherein the diaphragm part is disposedbetween the ejection port and the pressure reduction channel part in theflow channel.
 8. A drip irrigation apparatus comprising: a flow pipethrough which irrigation liquid flows, the flow pipe including anejection port that extends through a pipe wall; and the drip irrigationemitter according to claim 6 disposed on an inner peripheral surface ofthe flow pipe at a position corresponding to the ejection port, the dripirrigation emitter being configured to control an amount of theirrigation liquid ejected from the ejection port.
 9. The drip irrigationemitter according to claim 6, wherein the central wall part has acircular shape in plan view and the peripheral wall part has an annularshape in plan view.